Effects of Shrinkage Reducing Agent and Expansive Admixture on the Volume Deformation of Ultrahigh Performance Concrete

Su Anshuang,Zhang Jiayang,Li Zhaoyu,Qin Ling,Zhang Shoujie

doi:10.1155/2017/6384859

Abstract

This paper investigated the influences of shrinkage reducing agent and expansive admixture on autogenous and drying shrinkage of ultrahigh performance concrete (UHPC) containing antifoaming admixture. The shrinkage reducing agent was used at dosage of 0.5%, 1%, and 2% and the expansive admixture was used at dosage of 2% to 4% by mass of cementitious material. The results show that the air content of UHPC increases with the higher addition of shrinkage reducing agent and expansive admixtures. However, the fluidity, compressive strength, and shrinkage of UHPC exhibit a declining tendency. The usage of expansive agent at dosage of 4% significantly reduces the shrinkage of UHPC. The 7-day autogenous shrinkage was decreased by 16.0% and 28-day drying shrinkage was decreased by 29.5%, respectively. Shrinkage reducing agent at dosage of 2% reduced the 7-day autogenous shrinkage by 44.3% and 28-day drying shrinkage by 50.2%. Compared with expansive admixture, shrinkage reducing agent exhibits more efficient shrinkage reduction effect on UHPC.

Highlights

As a new generation of concrete, ultrahigh performance concrete (UHPC) possesses numerous advantages such as high strength, high durability, high reliability, and high performance [1]
This paper investigated the effects of shrinkage reducing agent and expansive agent on the shrinkage of UHPC mixed with antifoaming admixture and proposed some suggestions for future research work
It could be found that the fluidity of UHPC decreased with the increase of dosage of shrinkage reducing agent

Summary

Introduction

As a new generation of concrete, ultrahigh performance concrete (UHPC) possesses numerous advantages such as high strength, high durability, high reliability, and high performance [1]. In France, the guide “Ultrahigh Performance Fiber Reinforced Concrete-Interim Recommendations” described ultrahigh performance fiber reinforced concrete (UHPFRC) as a highly viscous cement based composite material with the 28-day compressive strength over 150 MPa, mixed with the steel fiber to increase toughness and mixed with fine quartz sand as aggregate [2]. Japanese Civil Engineering Society defined UHPC as a cement based material reinforced by steel fiber with 28-day compressive strength over 150 MPa and mixed with cement and highly active volcanic ash as cementitious materials [3]. The diameter of aggregate was less than 2.5 mm and water-to-binder ratio was less than 0.24. The research and application of UHPC in China are still in the experimental stage and the accumulation of experimental data and engineering experience is very necessary

Methods

Results

Conclusion